Fix Upbound email domains

We're upbound.io. upbound.com is a different business.

Signed-off-by: Nic Cope <nicc@rk0n.org>

OWNERS.md

@@ -11,8 +11,8 @@ This page lists all maintainers for **this** repository. Each repository in the
 repository maintainers in their own `OWNERS.md` file.
 
 ## Maintainers
-* Nic Cope <negz@upbound.com> ([negz](https://github.com/negz))
-* Sergen Yalcin <sergen@upbound.com> ([sergenyalcin](https://github.com/sergenyalcin))
-* Fatih Turken <fatih@upbound.com> ([turkenf](https://github.com/turkenf))
+* Nic Cope <negz@upbound.io> ([negz](https://github.com/negz))
+* Sergen Yalcin <sergen@upbound.io> ([sergenyalcin](https://github.com/sergenyalcin))
+* Fatih Turken <fatih@upbound.io> ([turkenf](https://github.com/turkenf))
 
 See [CODEOWNERS](./CODEOWNERS) for automatic PR assignment.